Most of the components of power system generation, transmission or distribution facilities, such as transmission lines, step-up and step-down transformers, power breakers and generators are monitored and controlled. The control and monitoring is usually performed by electromechanical or electronic equipment that are able to measure electrical quantities, perform calculations based on pre-defined algorithms and thresholds and actuate the system when necessary. Due to the high voltage, current and power flowing through the high-power components, current transformers, potential transformers and breakers are employed as an interface between the high-power components and the low-power control and monitoring devices such as a medium to high voltage monitoring circuit. This medium to high voltage monitoring circuit and its associated circuitry are tested by technicians. For example, a technician might test the operation of a medium to high voltage monitoring circuit or its associated circuitry by inserting a disconnect plug into an interface test device and performing various tests. Unfortunately, it is inevitable that mistakes happen during such testing which results in damage to the equipment or harm to the technician. During such testing, the technician might also adjust the medium to high voltage monitoring circuit by changing the parameters of the medium to high voltage monitoring circuit based upon the testing or based upon other factors. Unfortunately, such testing and adjustments take substantial amounts of the technician's time which is expensive. Furthermore, it is typical to perform period maintenance on the circuitry of the medium to high voltage monitoring circuits. In order to perform maintenance on medium to high voltage monitoring circuits, the associated power circuits must be powered down to allow the technician to perform the maintenance since the interface or other components in the medium to high voltage monitoring circuit might otherwise be damaged. These interruptions in operation of the medium to high voltage monitoring circuit and in the power circuit increase the cost of operation. For example, there are costs associated with switching to another power circuit and there are costs associated with the lost usage of the equipment powered by the power circuit. Accordingly, there is a strong need in the art to improve medium to high voltage monitoring circuits and their associated circuitries to reduce or eliminate the aforementioned drawbacks. Several different types of test interfaces are known in the power industry.
Test interfaces to be used for testing of substation devices can be inconvenient or cumbersome to activate due to problems of manually disconnecting the monitoring circuits from the system lines to the devices. One version of said interface works with a test plug to be inserted into a test block. Said test plug can be particularly difficult to insert, if it consists of many modules, i.e. covers many poles, which need to be inserted simultaneously. To aid in the insertion process of the plug, the current invention provides a leverage mechanism which is incorporated into the plug and renders possible a particularly smooth insertion of easy motion. In addition, a fastening mechanism is provided which guarantees that the plug fingers are precisely aligned with the block openings and the lever can be turned to accurately push the plug fingers into the block. The construction of the test plug is such that the plug is as light as possible and as solid and robust as possible to endure a high number of plug-in mounts.
Electromechanical or electronic devices such as relays and reclosers are typically installed in substation facilities and connect to medium to high voltage power lines via so-called monitoring circuits. The purpose of said devices is to monitor the operational power grid, e.g. protect grid sections from faults or record in-situ values at specific grid locations. The proper operation of said devices needs to be verified frequently over their entire lifetime. To this end, functional tests are undertaken at regular time intervals which indicate whether there is a defectiveness in any of their built-in functions. To facilitate an efficient testing process, it is common practice to use permanently installed test interfaces which are integrated into the monitoring circuits. Said test interfaces both provide a simple and safe disconnect functionality for any connected device.
The invention provides multiple improvements over the inventions described in U.S. Pat. Nos. 8,031,487 and 8,461,856 co-owned by Applicant, both of which are incorporated in their entirety by this reference.